Introduction

This chapter looks at a number of ways in which various aspects of risks to life (or limb) can be assessed and treatment decisions made. The discussion is divided into three parts. Sections 11.2 and 11.3 deal with the concept of total risk. Section 11.4 deals with the assessment of medical risks, illustrated in Section 11.5 by the smoking controversy. Sections 11.6 and 11.7 then deal with the problems facing the doctor in a therapeutic situation, linking assessments of probability with those of utility, and suggesting expectation of life as a useful measure of utility for decision purposes. Chapter 12 returns to the discussion of outcome values, and attempts to link the kinds of risks discussed in this and other chapters to the costs of risk avoidance or minimization measures in the public policy domain.

The total risk concept

The total cost (or loss) to society of many endeavours is not always solely the main items apparently ascribed to the endeavour. Thus the social cost of constructing a large building is not just the direct building costs and the cost of the one fatal accident that occurred on site, but also the costs corresponding to the physical risks involved in producing the various raw materials needed, making the steel and bricks, transporting the products, etc. in terms of deaths, sickness and disabilities. Although many of these deaths and injuries are ‘statistical’ in the sense that they cannot be identified as being directly linked to the project concerned, it seems reasonable to include and not discard such deaths (and accidents) on an average statistical basis.